In recent years there has been an tremendous expansion of interest in the design of new and improved fasteners which has matched the expansion of the use of strap carried backpacks for adults and school children, hikers and the military. The result has been that easy release fasteners have been produced employing mating engaging plastic parts of easily moldable materials such as nylon and the acetyl resin of the type sold under the trademark DELRIN. Innovative designs have produced easy engagement buckles with acceptable reliability.
When the requirement of easy release is added to the design requirements, the danger of unintended release becomes a real challenge to the buckle designer. When a buckle must be released by a single hand, one or two fingers, in a matter of a second or two, the danger exists of some unintended intervening action releasing the buckle. Examples of such intervening actions are brushing against branches or structures or casual contact of a hand or an object carried with the buckle. In the case where the buckle is on a belt, there may be a loss of the entire belt and its carried equipment. In the case of buckles on a backpack strap, the unintended release at the least is a distraction which may result in a possible accident to the wearer of the backpack. In the case of military applications, quick release of a buckle may also be critical in a tactical situation where unintended release may be life threatening.
The need for quick release buckles, particularly for military applications, is well described in U. S. Pat. No. 5,205,021 which discloses a two part plastic buckle with a flexible tongue with an enlarged end, designed to be easily grasped by a gloved hand to release the buckle.